Flaming swords are probably less deadly than normal swords because a flaming sword will cauterize the wounds it inflicts.

@howtofightwrite is this true? Need to know for story purposes

The true issue with the flaming sword is that the wielder is far more likely to set themselves on fire. Watch the making of from The Scorpion King where they talk about trying to do the flaming sword with practical effects and what a mess it ended up being. Douse it in oil and the fire goes everywhere.

Even if you’re keeping it mostly stationary but tilted, the oil will come running down toward your hand and bring the fire with it.

You’ve got a better chance with a magical sword enchanted with flame and the wielder being either A) a dragon or B) a mage who has enchanted themselves to be flame proof or C) made themselves flame proof by some other means or D) it’s an illusion meant to bluff.

If you can get the flaming sword to work in a manner that doesn’t endanger the wielder, then it’s going to actually be more dangerous than a regular sword simply by virtue of the intimidation factor and it’s ability to set it’s enemies on fire.

So, while it’s true that a flaming sword would cauterize the wounds, it doesn’t actually make it any less deadly unless the wielder intended to kill their opponent via bleedout.

I’ll be honest when dealing with bladed weapons blood loss is usually the point and what makes them so deadly. Like with any physical exertion, fighting raises your heart rate. Blood starts pumping through your body faster than it does normally because that oxygen needs to be carried to your muscles to keep them working. When your body is full of holes, especially holes near important arteries, that leads to the blood you need to survive leaving the body quicker.

If you are reading this and hadn’t realized yet that combat mechanics specifically exploit the human body’s inner workings, natural instincts, and psychology to achieve murder then yay, now you know.

Once you realize this, however, any hero who fights with their “natural instincts” so the author doesn’t have to explain why they suddenly know how to fight looks really silly.

Combat is a science, it is the reverse of medicine. It engages in manipulation and exploitation of the human body and psyche.

So, a flaming sword falls into the second combat category. It isn’t about efficiently exploiting the human body, but rather the human psyche and exploit it’s natural self-preservation instincts.

A flaming sword is here to terrify the ever living shit out of you.

It’s a common practice in torture, for example, to cauterize wounds inflicted because it ensures your victim remains alive, fire is scary, and the experiencing their flesh burning just ratchets up the terror factor.

If your character is not in danger of being burnt themselves, they’re fine with terror as a battle tactic, cool with the idea of their enemy dying an even slower and more painful death, and don’t have a problem accidentally burning their allies or setting the battlefield on fire, then there’s not a lot of downsides.

The burns will also hurt their enemy’s ability to move and their ability to fight, while the fire itself makes their opponent more cautious or even less likely to engage. This is especially true if the opponent is unarmored. Where even when defending, their chance of being scorched or set on fire is high.

The problem with fire is that it’s difficult to control, it leads to a lot of collateral damage, and will, you know, kill you in a very painful way. Battlefields are full of detritus that can quickly catch a blaze and once it takes off, whoosh.

You’ll note that the historical uses for fire in combat involve it being used as a defensive and deterrent method from positions where the defender’s own forces were unlikely to be harmed.

Imagine for a moment that your warrior is a dragon or a half-dragon, they are inherently flame proof but they oil up their sword anyway before going into battle or a duel and set it on fire with pyromancy. As they fight the oil drips on them, sets them on fire, drips on their opponent and sets them on fire, sprays everywhere and sets everyone on fire.

Their armor is burning. The oil is seeping in between the cracks and carrying the fire with it. Everything is getting hotter, hotter, and hotter like they landed smack in the fires of hell.

The dragon/half-dragon keeps right on going though, entirely unchecked by the fact that they are on fire, while their opponent is stumbling, screaming, and running as blind panic begins to set in.

Once you defeat your enemy in their mind, you win the fight. So, if your warrior’s primary goal is terror and psychological warfare then a flaming sword is fantastic choice. They want to keep their opponent alive to prolong their suffering and slowly roast them as a means of terrifying everyone else.

Psychological warfare is a legitimate reason to take this option, especially if the sword wielder cannot be burnt. Fire is terrifying. Trying to maintain a clear head amidst smoke inhalation and your flesh burning with each strike is going to be very difficult if not impossible.

If you’ve been burned before, any kind of burns, even low-grade ones, think about trying to move or think or defend yourself. It’s hard.

So, if your character’s primary goal is not combat effectiveness but intimidation and terror then the flaming sword is a decent option. Especially if the enemy has no idea how they managed to flame proof themselves.

If they can’t though, then it’s a bad option for the same reasons that it’s scary to other people.

No one wants to be set on fire.

No one wants to set themselves on fire.

No one wants their friends set on fire.

No one wants their supplies set on fire.

No one wants to see their castle and it’s inhabitants burning.

Fire is bad.

The question is: are the risks worth the reward?

Especially when you can get similar results more safely by wielding a torch in one hand and a sword in the other like Aragorn in Lord of the Rings. (9/10 the answer is no.)

Basically, if your character is wielding a flaming sword then they’re taking the Tarkin approach.

“Fear will keep the enemy in line, fear of this battlestation.”

– Grand Moff Tarkin, Star Wars: A New Hope